Brachystegia allenii

Brachystegia allenii Burtt Davy & Hutch.

Common names

Escarpment blue-leaved Brachystegia (English); chifuku (Bemba/Nyanja); msenga (Kunda/Nyanja); chalala, mchifuku, mbata, mvukwe, towe, twitwi, musumbu (Nyanja); mufunda-nzizi, twitwe (Tumbuka).

General description and distinguishing characteristics

This is a tree up to 10 (15) m, with a rounded crown, although it is often much smaller than this depending on the soil type on which it is found. Brachystegia allenii is one of the more easily recognised Brachystegia species, due to its distinctive oblong, cabbage blue leaflets which are twisted into a plane at right angles to the leaf stalk. This species is most conspicuous towards the end of the dry season when it produces new leaves of the deepest maroon-red. Bark: Grey, smooth to flaking, often with deep vertical fissures on mature specimens; smooth grey on branches. Stipules conspicuous and up to 2.5 cm long. Leaves: Alternate compound paripinnate with 3-5 (up to 6) pairs of leaflets on each leaf. Leaflets orbicular to oblong-elliptic with an emarginate apex, and cordate base; subsessile and arranged obliquely on the rachis (leaf stalk). Typically 3 x 4 cm, blue-green glaucous on both surfaces. Flowers: Produced in terminal racemes, the sweetly scented regular flowers have rose pink to green sepals and a cream coloured corolla (diameter up to 1.5 cm). They are produced at the end of the dry season (October-November). Fruit: A flattened rhomboid pod, grey-green when young, pink-brown when more mature, becoming woody and dehiscing explosively with age. Typically 3.5-4.5 x 8-9 cm; persisting on the tree all the year round, but bursting at the end of the dry season after flowering. The seeds are disc like and approximately 1 cm in diameter.

Range and habitat

Brachystegia allenii is widespread in Zambia and Malawi at altitudes ranging from 500-1400 m, and also occurs in Mozambique, Tanzania, DR Congo and Zimbabwe. In the valley Brachystegia allenii is tolerant of stony scarp slope soils, where it usually occurs as a small, stunted tree together with species such as Julbernardia globiflora and Brachystegia manga. On deeper, sandy soils it grows to its full height and may be found in association with Erythrophleum africanum, Burkea africana and Julbernardia globiflora. B. allenii is generally a lower escarpment species, typically being found on the colluvial soils of hill miombo woodland.